How to connect antenna base to powder-coated steel?

Ever heard of General Electric anti-oxidant paste?

Dissimilar metals in intimate contact are ONLY a problem for those who do not spend time resolving them.

Silver filled epoxy, followed by conformal coating over the exposed epoxy fillet. Job done. Problem solved.

It's 2.45GHz and powder coat is quite thick.

Four hours at 80C is "nothing"? You've got to be kidding. I ran a place with production for several years and turned that division around to profitability. So I know a thing or two about production, and 4h at 80C does not fly with large sheet metal items.

That leaves the bare unplated steel. Meaning we'd have to pot that up later and that is a highly undesirable step in system assembly. Then we'll rather go the stainless custom bracket route. Less $$$.

Yes, dumbfuck. If it is needed to perform the task, then it has to be there. You don't take an idiot like you, going around cutting corners and call it "streamlining". You're a total retard for that mindset alone.

You must have failed at it, since you are not still doing it.

Sounds like a deeper, stupid Mfgr with stupid processes in place to start with. Boilerplate stupidity begets boilerplate stupidity.

Not enough to know that you do what must be done to get to the finish line.

Are they going to cry, idiot?

You're an idiot. The US Military uses the very same epoxy on 100 Lb radio transceivers used in EVERY theater by EVERY ally, and they go through a 4 hour cure on the epoxy, and another 4 hour cure on the conformal coating. Those are completed units, fully assembled. They also go through both cycles whenever they come back in through the depot repair center, and get this element serviced.

You should. You should press a depression in the top of the box for a stainless plate add-in.

That way, emi gasketing mates the stainless to steel box, and a direct connection integrates the base plate and antenna. A few screws later, and you have boxes which can be painted beforehand, and antennas already mounted on plates that bolt right onto the box. Case closed.

Ever heard that companies can be _profitably_ sold?

Do you live in a cave? :-)

Then obviously another company wouldn't have bought us. Yet they did.

Oh, we will get there, we always do. Just not with 4h curing times.

You will have them if you ever need to implement the silver filled epoxy to facilitate a design.

Our BGAN portable radio has a fully hogged out Aluminum chassis. Well, each of the elements are fully hogged. THEN the get assembled into the finished box. Despite proper screw spacing and full mil spec level EMI chassis design elements being used throughout, it still failed Tempest emissions test miserably. At first, we had to hand fillet all the side wall and base plate seams with the epoxy. Then, they barely passed. Tempest emissions specs are VERY strict. Now, we have the metal shop vendor making them for us place the epoxy beads in the seams at assembly time, and they bake them before and after the powder coat sequence.

They did not piss and moan over several long bead placements AND an extra 4 hour cure cycle, yet you want to cry because of your convoluted semi-educated mindset about manufacturing processes. As a result, the radios pass muster, because the chassis is finally truly sealed against releasing any of the internal radiations being grabbed.

I haven't been following this thread, but when we've needed a conductive metal-to-metal contact (EMI reasons, normally) we masked off the powder coat and nickel plated the area. It wasn't at all expensive.

BGAN is used in the heavy duty and mil world. Very different market. Of course nobody will moan about a few bucks more. For much of my designs, very different thing.

Has it occurred to you that industrial real estate is not free? That curing ovens are not free? Do you know what overhead costs are and how they get charged to departments? It appears you need to brush up a bit in those areas.

Oh, and I am sure that in your miraculous world there are elves who bring the panels to and from the curing ovens without any pay whatsoever. Unless, of course, they are union elves ...

T'is exactly what I suggested and the shop turned that down :-(

I've used epoxy that was hard in something like 5 minutes

-Lasse

Me too, but it is definitely no fun. Even the 15 min stuff I often use is a pain. You mix it up hurriedly, work, and 5-10 mins into the game the stuff already begins to gunk up.

Then there is epoxy that is activated, for example by UV. But such processes are highly undesirable in the usual production environment unless the shop is already geared to do that. Then the fire marshal comes along and mandates a fume hood. Then the enviro guys show up and say you are polluting the air, causing polar ice to melt or whatever. Lots of bureaucracy and extra cost, BTDT. Best to avoid this stuff :-)

Cheers

Phil Hobbs

Joerg ...

Thanks,

Jim

That's not necessarily true.

Jim

Can you get them to spot-weld a standard nickel-plated washer to the case?

Best regards, Spehro Pefhany

Well, I almost have this project wrapped up by now (except for the layout). Found an extension cable that can be panel-mounted. Looks like gold-plated brass so we'll just have a strip made that has two holes. A big hole that goes under this bulkhead connector and a small one that goes onto the stainless stud right next to it. I just haven't made up my mind whether to use stainless or brass for the strip, it's very close on the galvanic table. I guess brass is much easier to machine.

Not ideal but low enough in inductance.

It'll be RP-SMA, then there's a much better selection of antennas.

Is it raining up in your area already? Dry down here but cold, the wood stove has been going all day.

Good idea. When I hand the design over to the client tomorrow I'll ask them to check into that. Although I am not too optimistic after their metal shop turned down the fairly standard Ni-plating request. Unfortunately it's all a bit cost-sensitive so changing shops isn't always in the cards here.